1. Field of the Invention
This invention relates generally to an improved heart valve prosthesis, and more particularly to such a prosthesis device which may be implanted to replace a defective natural or artificial heart valve and which incorporates electronics for monitoring and telemetering operational conditions of the valve and other biodata to an external receiver, as well as for providing stimulation pulses for pacing. The improved prosthesis device of the present invention employs at least one, but preferably two or even three occluder means, each in the form of a flat or curved plate or leaflet, both functioning hemodynamically by a periodic opening and closing motion which is created through normal pumping action of the heart. The improved prosthesis device may alternatively employ multiple occluder means, such as two or three flat or curved plates, or alternatively, a ball and cage check occluder. A sensor is incorporated for detecting such things as the movement of the leaflets and a transmitter/receiver (transceiver) is incorporated for sending and receiving data and commands from an external apparatus.
2. Discussion of the Prior Art
As is well known in the art, prosthetic heart valves function essentially as check valves. Blood flow, which occurs as a result of the natural pumping action of the heart, causes periodic opening of the leaflets, with the system pressure closing the leaflets during periods of diastole when in the aortic position or during periods of systole when in the atrial-ventricular position.
A variety of prosthetic heart valves have been proposed and utilized in the past. Certain of these prosthetic devices have employed a caged ball arrangement which also function and control blood flow in response to normal pumping action of the heart. The caged-ball designs have been found objectionable from a psychologic standpoint because of the audible clicking sounds emitted as the ball is made to seat and unseat relative to the opening in the valve body. Other heart valve prostheses have employed occluders in the form of either a round disk or a pair of semi-circular and semi-elliptical plates. The latter are normally referred to as bi-leaflet valves. While various materials of construction have been employed in the past, the more recently utilized heart valve prostheses have been fabricated essentially from pyrolytic carbon.
Bi-leaflet valves normally employ a strategically designed pivot means to appropriately guide and otherwise control the motion of the leaflets as they are made to move between their open and closed dispositions. In addition, means have been provided to control or limit the extent of motion to which the leaflets are subjected during opening and closing, thereby providing an arrangement wherein the motion of the individual leaflets is carefully guided, controlled, limited and maintained.
It is further known that blood components, including those cells normally found in human blood, are extremely fragile and delicate. These cells can be damaged and/or destroyed if subjected to unusual mechanical forces. Thus, care must be taken to control the nature of the forces created during the occurrence of relative motion between the leaflets and their surrounding annular body. For example, reduction of the occurrences of rubbing contact between stationary and moving surfaces is of importance when such contact is likely to cause mechanical damage to the various cell types present in blood. The design and configuration of the heart valve prosthesis of the present invention is such that care has been taken to reduce the creation of zones or areas where blood passing through the device is exposed to substantial mechanical forces. As such, the operation of the valve of the present invention is practically noiseless and conventional acoustic techniques cannot be used to assess operational performance of such "silent" valves. Accordingly, it is desirable that some alternative method of monitoring valve performance and other physiologic parameters be incorporated in or with the valve.